Sears Roebuck & Co. weren't the only ones selling packaged home kits way back when. In England, corrugated iron prefabs were being sold in the 19th century.

From the UK Independent:

Cheaply erected, flat-pack corrugated iron homes and farm buildings were once common in the Highlands but most have been torn down. The three-bedroom Ballintomb Cottage is one of the last still standing. In Edwardian times, a local farmer ordered it from the catalogue of a London company and had it delivered by steam train, then horse and cart, to a site near the village of Dulnain Bridge in Strathspey. He assembled it by hand, so he could move his family in during the summer while he rented out his farmhouse to wealthy holidaymakers. It cost just £425. Now, offers of more than £175,000 are being invited but the selling price could reach as much as £250,000.

These days, most of us associate corrugated iron with those cheap, crudely assembled homes packed together in slums across the developing world but, in the 19th century, it was one of the inventions in which Britain took pride. It was exported all over the world to make buildings of every size.

The construction of these iron buildings was fully detailed in the catalogues. They quote that "sheets of standard Birmingham grade galvanised iron are used, truly and evenly corrugated, thickly coated with pure Silesian spelter, true and even in temper, and free from flaws and cracks." Floorboards were supplied of thoroughly seasoned deal in 1" thicknesses and lining boards in 1/2" tongue and grooved. The walls were insulated by a liberal use of felt....

These buildings were sent to every corner of the Empire and Ballintomb Cottage is an excellent example of the quality of these buildings